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At least 19 recordsLinked to original sources
PubMed1977

Sites of the 5S ribosomal genes in Drosophila. I. The multiple clusters in the virilis group.

Drosophila melanogaster 125I-5S RNA was annealed to salivary gland preparations of 6 species in the virilis group of Drosophila. Two patterns of annealing were found. D. virilis, D. montana and D. borealis showed three 5S gene clusters on chromosome 5; Sd-f and Wc-j were strongly labeled, but Xa-e was weakly labeled. D. montana and D. borealis have a greater percentage of their total 5S cistroms at S d-f than does D. virilis. D. americana americana, D. americana texana and D. novamexicana showed 2 sites labeled; no label was seen at Sd-f while Wc-j was weakly labeled and Xa-e was strongly labeled, the reciprocal of the previous pattern in the W-X region. Hybrids between D. a americana and D. virilis showed no difference in chromosome banding at the sites of the 5S clusters despite their pattern difference. D. a texana X D. virilis, on the other hand, did show a difference in staining the Xa-e region. These patterns fall squarely into the biosystematic groupings deduced by many previous workers.

Animals↗
PubMed1992

Histomorphological and immunohistochemical evidence that human nodular goiters grow by episodic replication of multiple clusters of thyroid follicular cells.

This study was aimed at dissecting the cellular mechanisms that underly the growth of actively expanding human goiter nodules. Thirty-two nodules from different patients, all removed because of steady recent growth, were serially sectioned and screened for 1) histomorphological signs of cell proliferation and 2) in situ expression of the immunohistochemically stained p21ras protooncogene product. Bovine, porcine, and rat thyroid glands (the latter from both T4- and perchlorate-treated animals) were used as controls. In normal glands, only a few follicular cells contain substantial amounts of stainable p21ras. Some of these cells are unusually large, but do not proliferate. In contrast, all goiter nodules contain areas where the epithelial cells are morphologically grossly altered and heavily loaded with p21ras. Cells of this type are mostly clustered in large cohorts coating whole follicles or entire groups of follicles. Only a small fraction of these activated cells actually proliferates at any one point in time. Actively replicating cells are scattered in tiny foci all over the nodules. The earliest proliferating buds are solid, but soon begin to generate microfollicles that enlarge by adding new cells to the follicular epithelium. Regionally heterogeneous p21ras content in morphologically identical cells suggests that growth occurs in bursts and waves. We conclude that goiter nodules grow by episodic proliferation of heterogeneous cohorts of epithelial cells from which new follicles are generated. Only a tiny fraction of all goiter cells proliferate at any one point in time. The molecular mechanisms governing these growth processes are unknown.

Adolescent↗
PubMed1992

[Cluster and multiple regression analysis of leptospirosis epidemic factors].

Ten-year surveillance of Rice-field-typed leptospirosis was carried out in high-infected foci. Twenty two parameters of epidemic data were divided into 3 categories and cluster-analyzed. 5 typical variables were selected for multiple regression equation. The equation contained four factors, i.e. rodents density, carriage rates of main animal hosts, GMT of population antibody against leptospira and quantity of rainfall in August. The expected morbidity of leptospirosis calculated by the equation were roughly identical to the real morbidity.

Animals↗
PubMed1976

Studies on the clustering of multiple sclerosis in Finland.

The epidemiological investigation of multiple sclerosis (MS) in Finland revealed a prevalence rate of 40.3 per 100.000 inhabitants. The geographic distribution of MS was uneven in the country. MS seemed to occur more often in the western and southwestern parts of the country, where the prevalences varied between 51.7 and 62.1 This phenomenon became even more pronounced when the distribution of the disease was investigated in small geographic units. Optic neuritis showed a geographic distribution similar to that of MS, with clustering in the same parts of the country and even in the same narrow districts. The correlation between the birthplaces of MS and optic neuritis patients was very significant (p less than 0.001), which suggest that they share a common aetiology. The possible aetiological role of genetic and exogenous factors was discussed in the western cluster of MS, where the percentage of familial cases was 13 and an accumulation of muscular dystrophy of cattle was observed.

Finland↗
PubMed1975

Studies on the clustering of multiple sclerosis in Finland I: Comparison between the domiciles and places of birth in selected subpopulations.

Further studies pm yjr rofr,op;phu pg ,i;yo;r dv;rtpdod (MS) IN Finland were carried out in three different types of geographical unit: in counties, combined clerical districts, and single clerical district. For longitudinal studies, the prevalence of MS by present domicile was compared to that by place of birth, and also to the number of MS cases in relation to the number of births. The analysis was based on 1,866 living MS patients. The highest prevalence by present domicile was recorded in the southwestern county of Turku and Pori (52.3 cases per 100,000 inhabitants). It was 39.6 for the whole country. Two separate clusters were found at the level of combined and single clerical districts: one in the western county of Vaasa, and another in the southwestern county of Turku and Pori. The highest prevalences by present comicile were found in two clerical districts of Vaasa (83.5 and 79.7). They also had very high prevalences by place of birth. They lie close to each other, but are not immediate neighbours. Another high-risk focus was revealed in an area of the neighbouring districts of Turku and Pori. In fact, the two highest prevalences by place of birth were found in this region (123.1 and 95.0). The focus extended from the coastal area to the more central region of the county, and further to the western districts of the otherwise medium-risk county of Hme. Thus, two separate foci were found in Finland: one in the western and another in the southwestern part of the country. The clustering became even more pronounced when the prevalences by place of birth were analysed. Considering that the Finnish population still largely originates from genetic isolates of varying degrees, gene enrichment explains the clustering at least partly.

Adult↗
PubMed1975

Studies on the clustering of multiple sclerosis in Finland II: microepidemiology in one high-risk county with special reference to familial cases.

The epidemiology of multiple sclerosis (MS) was investigated in a small selected area within the western high-risk county of Finland. The investigation was extended to the level of single communes, villages and even houses, together with the search for all familial cases born in this district. The results were compared to those obtained for Helsinki, a city of medium-risk for MS. Prevalences by present domicile that exceeded 100 per 1000,000 inhabitants were recorded in several communes of the western high-risk county. The highest prevalence was 174.2. Seventy patients were born in the small high-risk area. This was 25% of the MS patients born in the whole county and much higher than expected (16%). A positive familial history of another MS patient was recorded in 8 cases (11%). They were all living, first-degree relatives. A similar history was found in only 2 cases (2%) among the 99 MS patients born in Helsinki. The birthplaces of the 123 parents of these 70 MS cases could be confirmed. All villages with high MS frequencies were located along the rivers, running through the area. The birthplaces of the patients showed a similar accumulation to the valleys. No conjugal cases were found. If the preponderance of familial cases in the small high-risk area reflects the role of genetic factors in the aetiology of MS, it is only of polygenic nature. The pronounced clustering of the birthplaces in the small high-risk area and, especially, along the rivers also suggests the importance of environmental influences in early childhood.

Child, Preschool↗
PubMed1978

Functional organization of receptive fields in the cat somatosensory cortex. I: Integration within the coronal region.

The receptive fields (RF) of the neurons in the coronal region of the first somatosensory cortex (SI) were studied in a preparation of unanesthetized paralyzed cats. The majority of units responded to simple light mechanical stimuli to the hairy or glabrous skin. There were units with slightly larger RFs and more complex properties, such as those preferentially responding to the moving skin stimuli with directional selectivity. The receptive fields tend to be larger in the more rostral (area 3a) or medial coronal (area 3b) region than in the caudal region (area 3b). The largest RFs intermingled among focal ones included other smaller RFs in the vicinity. Their configurations were different at different loci in the coronal region. It is suggested that the coronal SI region is organized in terms of multiple clusterings of units, each with particular receptive field characteristics. The representation of a single peripheral locus on the forepaw can thus be multiple, if it appeared in more than one of such clusterings of receptive fields.

Animals↗
PubMed1979

Considerations in applying clustering techniques to speaker-independent word recognition.

Recent work at Bell Laboratories has demonstrated the utility of applying sophisticated pattern recognition techniques to obtain a set of speaker-independent word templates for an isolated word recognition system [Levinson et al.,IEEE Trans. Acoust. Speech Signal Process. ASSP-27 (2), 134--141 (1979); Rabiner et al., IEEE Trans. Acoust. Speech Signal Process.(in press)]. In these studies, it was shown that a careful experimenter could guide the clustering algorithms to choose a small set of templates that were representative of a large number of replications for each word in the vocabulary. Subsequent word recognition tests verified that the templates chosen were indeed representative of a fairly large population of talkers. Given the success of this approach, the next important step is to investigate fully automatic techniques for clustering multiple versions of a single word into a set of speaker-independent word templates. Two such techniques are described in this paper. The first method uses distance data (between replications of a word) to segment the population into stable clusters. The word template is obtained as either the cluster minimax, or as an averaged version of all the elements in the cluster. The second method is a variation of the one described by Rabiner [IEEE Trans. Acoust. Speech Signal Process. ASSP-26 (3), 34--42 (1978)] in which averaging techniques are directly combined with the nearest neighbor rule to simultaneously define both the word template (i.e., the cluster center) and the elements in the cluster. Experimental data show the first method to be superior to the second method when three or more clusters per word are used in the recognition task.

Humans↗
PubMed1992

Patterns of projections from area 2 of the sensory cortex to area 3a and to the motor cortex in cats.

Peripheral information reaches the motor cortex partly through corticocortical pathways that arise from two functional subdivisions, area 2 and area 3a, of the sensory cortex. These sensory areas are synaptically linked with one another. The patterns of connectivity and the different submodality input that each area receives suggest that they send different efferent signals to the motor cortex. The projections from area 2 to area 3a and to the motor cortex were studied with retrogradely transported fluorescent tracers. The pattern and distribution of neuronal labeling in area 2 was determined following injections of different tracers into the forelimb regions of area 3a and the motor cortex. The results showed that the projections from area 2 to the two target regions were topographically and somatotopically related. Multiple clusters of motor cortex projection neurons were found in area 2, and these clusters overlapped extensively with clusters of area 3a projection neurons. Although cells labeled with one of the dyes were often in close proximity to cells labeled with the other dye, no double-labeled cells were found. Two different laminar patterns were seen for the two populations of neurons. The projection to area 3a originated from cells located in layers II-III and layers V-VI. The projection to the motor cortex originated from cells spread throughout layers II-IV, but predominantly in layer III. Differences in laminar arrangement of the two populations of cells suggest a directional flow of information processing in the sensorimotor cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1975

Benign lymphoid polyps of the rectum.

Benign lymphoid polyps are a rare histologic entity and should not be confused with malignant disease of the colon and rectum. Although retention polyps are the single most common type of colonic polyp in children, the presence of multiple clustered polyps in the rectum should alert the radiologist to the possibility of benign lymphoid polyps. A representative case is described and a review of the pediatric experience with this entity is discussed.

Child↗
PubMed1977

Comparative study of hen yolk phosvitin and plasma vitellogenin.

Vitellogenin, the only phosphoprotein detectable in the plasma of laying hens, is present at an approximate concentration of 1 mg/mL and can be isolated by chromatography on diethylaminoethylcellulose. Vitellogenin has a molecular weight of 235 000--240 000 and contains approximately 3% phosphorus by weight. Evidence that this protein is the precursor of phosvitins includes its ability to act as an acceptor for phosphate with a phosvitin specific kinase, the generation of a peptide similar to phosvitin by trypsinization, and the presence of distinctive peptides of multiple clustered phosphoserine upon partial acid hydrolysis. This partial sequence similarity between phosvitins and vitellogenin has not been previously reported. The phosphorus content and amino acid composition of vitellogenin are consistent with a model which contains two phosvitins and one lipovitellin. The total molecular weights of these proteins (28 000 + 34 000 + 170 000 = 232 000) are close to that of vitellogenin.

Amino Acids↗
PubMed1992

[Are disturbances of small intestinal motility associated with hyperglucagonemia in patients with liver cirrhosis?].

Patients with liver cirrhosis develop marked abnormalities in small bowel motility and high plasma glucagon levels. Disturbances in small intestinal motor activity could be related to hyperglucagonemia. To investigate the relationship between fasting plasma glucagon levels and changes in small bowel motility in patients with liver cirrhosis, eighteen cirrhotic patients and ten controls were studied. Plasma glucagon was measured by RIA. Mouth to cecum transit time was estimated by lactulose hydrogen breath test. Fasting small bowel motility was investigated by means of intraluminal manometry. Plasma glucagon levels were significantly higher in patients with cirrhosis (61 +/- 5 pmol/l) than in controls (32 +/- 3 pmol/l); p < 0.01. In patients with liver disease, plasma glucagon levels were not significantly correlated to mouth to cecum transit time (r: -0.32), duration of migrating motor complex (r: -0.24), nor to the frequency of multiple clustered contractions (r: -0.26). The degree of small bowel dysmotility is not related to plasma glucagon levels in patients with hepatic cirrhosis. These results do not support the hypothesis that hyperglucagonemia plays an important pathogenic role in the abnormalities of gut motility in cirrhosis.

Adult↗
PubMed1976

A test for randomness.

A procedure is proposed for studying the hypothesis that a sequence of dichotomous random variables are independent and identically (randomly) distributed. The procedure is relatively sensitive to departures from randomness involving multiple clustering. An application to testing for Schwann cell disease is discussed. The distrubution of the sample coefficient of variation from an exponential distribution, a useful statistic in testing randomness for a continuous model, is also studied.

Biometry↗
PubMed1992

Multivariate methods for clustered binary data with multiple subclasses, with application to binary longitudinal data.

Clustered binary data occur frequently in biostatistical work. Several approaches have been proposed for the analysis of clustered binary data. In Rosner (1984, Biometrics 40, 1025-1035), a polychotomous logistic regression model was proposed that is a generalization of the beta-binomial distribution and allows for unit- and subunit-specific covariates, while controlling for clustering effects. One assumption of this model is that all pairs of subunits within a cluster are equally correlated. This is appropriate for ophthalmologic work where clusters are generally of size 2, but may be inappropriate for larger cluster sizes. A beta-binomial mixture model is introduced to allow for multiple subclasses within a cluster and to estimate odds ratios relating outcomes for pairs of subunits within a subclass as well as in different subclasses. To include covariates, an extension of the polychotomous logistic regression model is proposed, which allows one to estimate effects of unit-, class-, and subunit-specific covariates, while controlling for clustering using the beta-binomial mixture model. This model is applied to the analysis of respiratory symptom data in children collected over a 14-year period in East Boston, Massachusetts, in relation to maternal and child smoking, where the unit is the child and symptom history is divided into early-adolescent and late-adolescent symptom experience.

Adolescent↗
PubMed2026

Genomic analysis of regulatory mechanisms governing EPS66A biosynthesis in Streptomyces changanensis HL-66.

Streptomyces changanensis HL-66 produces the &#x3b1;-(1,4)/(1,6)-glucan exopolysaccharide EPS66A, a potent plant immune elicitor with promising applications in plant protection. However, its low native fermentation yield limits large-scale application. To investigate the biosynthetic potential and regulatory mechanisms underlying EPS66A production, the whole genome of HL-66 was sequenced and analyzed. The HL-66 genome is 6.82&#xa0;Mb in size, with a GC content of 74%, and encodes 6081 predicted functional genes. Among these, 1390 genes were annotated to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, 4187 were assigned to Gene Ontology (GO) terms, and 143 were classified into Clusters of Orthologous Groups (COG) categories. antiSMASH analysis identified 22 secondary metabolite biosynthetic gene clusters, including multiple polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) clusters. Functional analyses revealed that the glycosyltransferase gene (GTy) and the global regulatory gene (bldD) are involved in EPS66A biosynthesis. bldD is involved in morphological development and EPS66A production, whereas GTy specifically regulates EPS66A production without affecting growth or development. In both in vivo and potted-plant experiments, EPS66A (200&#xa0;&#x3bc;g/mL) significantly reduced the severity of tobacco mosaic virus, apple anthracnose leaf spot, walnut bacterial leaf spot, and jujube anthracnose, achieving control efficacies of 90.21%, 87.95%, 77.41%, and 68.55%, respectively, and outperforming a commercial chitosan oligosaccharide control. These findings provide new insights into the genetic architecture and regulatory mechanisms of EPS66A biosynthesis and support its development as a polysaccharide-based green pesticide.

Streptomyces↗